1. Field of the Invention
The present invention relates to a bridge fiber, a combiner, and a fiber laser device that are suited for reducing light returning to a pumping light source from an amplification optical fiber.
2. Description of Related Art
There has been implemented a fiber laser device in which pumping light emitted from a pumping light source enters an amplification optical fiber through a combiner. In some cases, the fiber laser device of this kind experiences failure of the pumping light source when the light amplified by the amplification optical fiber returns to the combiner as return light and is propagated to the pumping light source through the combiner.
Patent Literature 1 has been disclosed as a measure to remove such return light. In Patent Literature 1, an anti-reflective film is attached at an entrance end of the amplification optical fiber in order to guide the light to the outside, the light being generated within the amplification optical fiber and having a specific wavelength.